Asian Pacific Journal of Cancer Care (Mar 2022)

CT and MRI Based Gross Tumor Volume Comparison in Pharyngeal and Laryngeal Carcinoma

  • Vinin. N.V,
  • Joneetha Jones,
  • Aswanth .K.Anil,
  • Akhil. P.Suresh,
  • Satheesh Babu. T.V,
  • Geetha Muttath,
  • Arun Kumar. E.S

DOI
https://doi.org/10.31557/apjcc.2022.7.1.65-69
Journal volume & issue
Vol. 7, no. 1
pp. 65 – 69

Abstract

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Background: Different other imaging modalities help in accurate gross tumor volume delineation. Studies have shown conflicting results for intermodality GTV comparison. Since in our institute we routinely take planning CT and planning MRI for laryngeal and pharyngeal tumors treated with definitive radiotherapy, with this study we intent to compare the gross tumor volume (GTV) with these modalities in these tumors. Materials & Methods: Study population included pharyngeal and laryngeal carcinoma patients treated. Planning CT and planning MRI images of these patients were retrieved. Gross tumor volume (GTV) was delineated by a Radiation Oncologist in both these image sets and GTVs were documented. Results: Out of 87 patients analysed, the overall median GTV with planning CT and planning MRI were 20.4 cc & 18.2 cc respectively. Median GTV with planning CT & MRI for different sites like Nasopharynx, Oropharynx, Larynx and Hypopharynx were 32.85 & 27.75 cc, 22.1 & 20.9 cc, 8.25 & 10.35cc and 20.55 & 20.6 cc respectively with no statistically significant difference. Median GTVs with CT & MRI for different primary tumor stages like T2, T3, T4a, T4b were 14.3 & 14.3 cc, 20.45 & 19 cc, 16.55 & 27.45 cc and 50.75 & 52.4 cc respectively. Analysis showed 94.6 % correlation between GTVs with CT & MRI. Conclusion: This study showed comparable median GTVs with planning CT & MRI for pharyngeal and laryngeal carcinomas. Subset analysis did not show any significant difference in GTVs with two modalities for different primary tumor site. As expected there was good correlation between GTVs of two modalities. Even though the results does not show significant intermodality variation for GTV delineation. With the results of this study we cannot question the use of multiple modalities for GTV delineation as subtle variation in GTV can result in differences in target volumes resulting in differences in toxicity profile.

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